Optimum Spatial Arrangement of Array Elements for Suppression of Grating-Lobes of Radar Cross Section
ABSTRACT A new method to optimize the radar cross section (RCS) for array antennas is presented. A previous work has reported that the RCS of an array is the product of the array RCS factor multiplying the element RCS factor. In this method, the strong scattering from an equally spaced array can be considerably reduced at some certain directions by optimizing the array RCS factor. With the proposed method, the optimized array will scatter waves at a much lower level against prescribed incident directions. In order to illustrate the validation of the proposed method, a planar dipole array and a linear array with bowtie antenna elements are designed and optimized by the proposed method. The numerical and simulated results show that the RCS pattern of equally spaced array generally has some grating-lobes at some certain directions. Hence, the proposed method is applied to suppress these grating-lobes to design a low RCS array. The algorithmically optimized and simulated results validate that the proposed method can help to suppress these grating-lobes.
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ABSTRACT: This letter extends the concept of the active element pattern method that is used to solve the array radiation problem when scattered fields of large finite arrays are calculated. We name this method the original induced element pattern method (OIEPM). The theoretical derivation of the method is presented. In addition, to overcome the limitation and simplify the operation of the OIEPM, an improved induced element pattern method (IIEPM) is proposed, which transforms the large array calculation problem into two small array problems. Unlike the OIEPM that requires calculation of the induced element pattern (IEP) of all the elements of the subarray, the IIEPM merely needs to calculate the fully scattered field of two small arrays. Meanwhile, the effects of the mutual coupling between elements and the edge diffraction are rigorously taken into account. Compared to other numerical and active (or induced) element pattern methods, the IIEPM can greatly reduce the computational cost and simplify the operational procedure. Examples of microstrip patch antenna arrays are analyzed to assess the accuracy and generality of the IIEPM. Numerical examples show that the scattering patterns calculated by the IIEPM and those simulated by the HFSS are in good agreement.IEEE Antennas and Wireless Propagation Letters 02/2011; · 1.67 Impact Factor
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ABSTRACT: Synthetic aperture radar (SAR) is a well-proven remote-sensing technique; however, current single-antenna SAR systems cannot fulfil the increasing demands for high-resolution and wide-swath imaging. This paper proposes a multiaperture antenna with waveform diversity for wide-swath remote sensing. This approach employs a multiple-transmit multiple-receive antenna configuration in elevation and an orthogonal transmit waveform. In this way, multiple pairs of virtual beams directed to different subswaths can then be formed simultaneously. Equivalently, a large swath can be obtained. Furthermore, orthogonal frequency diversion multiplexing (OFDM) linearly frequency modulated (LFM) waveform and beamforming on reception are employed in this paper. The system scheme, signal model, processing algorithm, signal-to-noise ratio (SNR), and ambiguity-to-signal ratio (ASR) performance, including both azimuth and range dimensions, are investigated. Simulation results show that the proposed method can obtain an improved range ambiguity suppression, thus enabling a wider swath for remote sensing.International Journal of Remote Sensing 06/2013; 34(12):4142-4155. · 1.36 Impact Factor